Tractor safety switch



Dec. 8, 1959 H. L. LolsELLE 2,916,573

TRACTOR SAFETY swITcH Filed April 2, 1957 HIS ATTORNEY 2,916,513 moronSAFETY swrrcn 4 vHenry Louis Loiselle, Toronto, Ontario, CanadaApplication April z, 1951, serial No. 650,201 1 ciniii.` (ci. zoo-ens)My invention relates totractor safety switches the primary objectwhereof is to. provide a simple and reliable, wholly mechanical meansconveniently purchasable and installable upon a tractor as an accessory,whereby the fuel supply or ignition system may be immediatelyinterrupted upon the excessive tilting of the tractor eitherlongitudinally, transversely, or so tilted in any direction, suchinterruption being calibrated to occur before the tilt becomes dangerousso that the tractor will become stalled at that angle.

A further object of the present invention is to provide means whereby agreater degree of tilt or inclination in longitudinal directions will bepermitted before the fuel or ignition is interrupted than will bepermitted in a transverse direction.

A further object of my invention is to provide means whereby theintertia member thereof may be free to rotate without inuencing itsability to act upon the associated follower piston.

With the foregoing more important objects in View, and such otherobjects as may become apparent as this specification proceeds, myinvention consists in the following arrangement and construction ofparts all as hereinafter more particularly described, reference beinghad to the accompanying drawing which is a vertical crosssection of myinvention.

It is well known that many accidents, frequently fatal have been causedby the overturning of tractors consequent upon their being driven on toinclined surfaces too steep for their operating centers of gravity. Thepresent invention will prevent tractors from being driven on to surfaceswhich are excessively steep by causing the fuel supply, ignition system,or perhaps some other point of vital operation to be interrupted in itsfunction before the tractor can be driven onto a surface which is toosteep for it. When such interruption occurs, it will be necessary forthe operator to re-set the device I am about to describe, and eitherhold it re-set until the tractor has been moved onto more nearlyhorizontal territory, or in some other way to provide for a temporaryresumption of the interrupted means of operation. Thirdly of course thestalled tractor could be pulled by another tractor onto more horizontalterritory.

Proceeding therefore to describe my invention, the same is to beunderstood as comprising a mounting structure collectively designated 1in the form of a preferably cylindrical casing 2 provided with aremovable base 3 and an overspanning portion 4 upon which is mounted anenclosing turret 5 for a cutout movement collectively designated 6.Within casing 2 and projecting downwardly and concentrically from theoverspanning portion 4 is an open-ended cylinder 7.

Movable within cylinder 7 is a follower piston 8 in the form of a cupsuitably splined to the cylinder 7 as at 9 to permit linear butnon-rotary motion. Such follower piston is diametrically lobed as at 10for a reason which will presently become apparent. The lobes soindicated United Sere Pw 0f 2,916,573 l'fatented Dec, 8., 1959 ICC 2 arealso preferably bilaterally situated for a` reason which also willpresently become apparent." K

Overspanning portion 4 is centrally aperturedas at 11 to permitprojection therethroughv of a thrust element 12 in the form of a rod thelower end ofv which bears against the crater-center of piston 8, whilethe upper end bears. against cutout movement 6 aswillpresently be moreparticularly described. Surrounding rod 12 is a spring 13, the upper end of which maybe saideiectively to bear against overspanning portion4`while'the lower end thereof, like the lower end of thrust yelement 12,bears" against the crater-center of follower piston 8.

Situated to swing freely at the lower open end of cylin-` der 7, andsuitably held in position as bymeans ofthe clips'14 is ahemi-sphe'rica'l rim-cam 15'forming part 'of af governor assemblycollectively'de'sgnated 16. The re' maining parts of saidgovernon'assembl'y comprise the' pendulum rod 17, and aninertiamemberorweighted ele. ment 18 secured-thereto. Cam lS-will :be observed as'slightly dished as at 19 to provide the actual cam rim 20 thereof.

The cutout movement collectively designated 6 comprises a bell-crank 21embodying an arm 22 and a foot 23, the foot being preferably capped asat 24 the more comfortably to accommodate the bearing end of thrustelement 12. Bell-crank 21 is journalled at 25 upon the upstanding earpiece 26. At approximately mid-point of the length of arm 22, a dog 27is provided.

To one side of cutout movement 6, an upstanding support collectivelydesignated 28 is provided. This support includes a clip 29 designed toreceive the Bowden cable 30. At the upper end of support 28, a hair-pinspring 31 is secured horizontally by one end thereof. The free andsubadjacent end 32 bears downwardly against dog 27.

The bared end 33 of Bowden cable 30 is anchored to the eyelet 34 on theupper end of arm 22, such eyelet being swivelable for preference so asto avoid torsion upon bared end 33 in the operation about to bedescribed.

When a tractor to which the device which I have now describedstructurally is attached, is permitted to incline longitudinally fromthe horizontal beyond a predetermined limit, the inertia member 18 willswing leftwardly or rightwardly with respect to the accompanyingdrawing. It will so swing to an extent sufcient to cause the camming rim20 to engage the annular region 35 of the conical undersurface 36 offollower piston 8 and move the same upwardly against the resistance ofspring 13. In so moving member 8 upwardly, thrust element 12 will alsobe caused to rise. This will rotate bell-crank 21 counter clockwise as Ihave indicated in phantom lines. In so moving, bell-crank 21 will movethe bared end 33 of the Bowden cable 30 leftwardly and thereby causeinterruption of an associated fuel supply system, ignition system, orother vital operating part. As dog 27 is also moved counter clockwise,the free end 32 of hairpin spring 3-1 will be compressed. When the pointof etfort exerted downwardly by the spring portion 32 is slightly to theright of the common central axial plane of journal 25 and dog 27, suchfree end 32 will snap arm 22 over into the irreversible (until manuallyre-set), or locked position indicated by phantom lines. Due to thefunctional description which I have given of cutout movement 6, Idesignate its action as self-locking and epicentric.

Diametrically opposed lobes 10 are intended to take care of excessivelateral tilt, as when the associated tractor is travelling at uniformaltitude along a hill-side. Obviously the rim 20 will then engage one orthe other of these lobes rather than the regions 35. Upon being socontacted, the same train of mechanical events will be initiated as Ihave already described.

In conclusion I would add that it is a convenience if a visual oraudible device actuated by inertia member 18 be associated with thisinvention in order that a signal be conveyed to the operator beforeinterruption occurs such as I have described, whereby the inconvenienceof resetting mydevice may,befavoided` y Since various modificationsl canbe made in my invention. as hereinabove described, and many apparentlywidely different embodiments of same made within the spirit and scopeofthe claim without departing from such spirit and scope, it is intendedthat all matter contained in the accompanying specification shall beinterpreted as illustrative only and not in a limiting sense.

,What I claim as my invention is:

A tractor safety switch comprising in combination a mounting structure,a cylinder thereon, a cutout movement, means for actuating said cutoutmovement comprising a piston having a pair of diametrically lobedfollowers, and inverted conical areas therebetween, said piston beingmovable within said cylinder, a spring actuated thrust element alsowithin said cylinder actuable by said piston, and a governor assemblyincluding a hemispherical cam having an upwardly projectingcam-rimsurrounding a dished center portion, an inertia member connected to saidcam responsive to change in the center of gravity of said tractor, formoving the rim of said cam into contact with said follower upon theexcessive tilting of said tractor, to actuate said follower piston andthereby said thrust element and cutout movement, said cutout movementbeing in the form of a bell-crank against one end of which said thrustelement is bearable, a dog on said bell-crank, a spring in contact withsaid dog, said bell-crank, dog and spring being so related as toconstitute an epicentric-throw whereby said cutout movement isself-locking upon actuation by said thrust element. f

ReferencesCited in the file of this patent UNITED STATES PATENTS1,411,298 Osborn Apr. 4, 1922 2,130,706 Salmond Sept. 20, 1938 2,176,770j Maught Oct.' 17', 1939 2,708,966 Davis May Q4, 1955 FOREIGN PATENTS790,543 i France Sept. 9, 1935

